First principles study of electronic and optical properties of [formula omitted] chalcogenides for photovoltaic applications

Abstract

In this work, we study the main electronic and optical properties of quaternary chalcogenide Ag2CdSnS4 crystallized in three structure configurations; kesterite (KS), stannite (ST) and PMCA. This study is carried out using the full potential linearized augmented plane wave (FP-LAPW) method, through the generalized gradient approximation (GGA) and the modified Becke Johnson (mBJ-GGA) as exchange correlation functionals. Through this study, the semiconductor nature of our studied compounds is highlighted using mBJ-GGA approximation. Moreover, band structure plots show that the studied compounds possess direct energy band gap situated at the Γ point of the Brillouin zone. The linear optical properties such as the dielectric function, the absorption coefficient, the reflectivity and the refractive index are also simulated. High absorption and low reflectivity at the visible and ultraviolet regions are among the main features of Ag2CdSnS4-based materials. These results seems to be in line with awaited characteristics of solar cell absorbers.